modify README and remove redundant file

third_party/incubator-tvm/README.md

 
-This is a tailored apache/incubator-tvm 0.6 for Auto Kernel Generator, k means kernel.
+This is a revised apache/incubator-tvm 0.6 for Auto Kernel Generator.
 What we are using:
 * TVM IR
 * Arith Simplify

third_party/incubator-tvm/README.md~

-# air
-
-This is a tailored apache/incubator-tvm 0.6 for Auto Kernel Generator, k means kernel.
-What we are using:
-* TVM IR
-* Arith Simplify
-* Several passes
-* DSL api
-* topi
-